1. Field of the Invention
The present invention relates to an improved arc reactor having an advanceable electrode for use in treating ores or other metallic or non-metallic compounds at very high temperatures in order to physically or chemically transform the same.
2. Description of the Prior Art
Arc reactors are well-known devices that have been made the subject of much research and development over the last decades. By definition, such reactors make use of a heat generating arc column between a set of electrodes to heat the ores or compounds to be treated at very high temperatures and thus allow reactions to occur that would otherwise not be obtainable. The arc column consists of a mixture energized and/or dissociated molecules, positively charged ions and free electrons obtained from a gas (hereinafter called "plasma gas") subjected to partial ionization by means of an electric arc (usually direct current) formed between an anode and a cathode.
More specifically, the electric arc reactor which is improved by the present invention is of the type having an upper electrode located in an upper sleeve chamber, and a lower electrode in conductive contact with the conductive molten ore placed in a crucible below the upper electrode. The arc column formed between the upper and lower electrodes melts the ore introduced in the sleeve chamber and causing the desired physical or chemical transformation, and the molten ore then falls into the crucible. Such reactors are described in U.S. copending application 399,997 filed Aug. 29, 1989, pending, which is incorporated herein by reference.
Arc reactors using "non-consumable" electrodes are currently used. However the lifetime of the so-called non-consumable electrodes varies between 3 and 1,000 hours depending on the operating conditions. Electrode replacement is expensive and often the reactor process has to be stopped.
Non-consumable electrodes in general, have to be water cooled otherwise the erosion will be too extensive. Water leaks in the reactor have happened in several cases and explosions have occurred because of the reaction of the water with the material being treated at high temperature.